The development of fully autonomously traveling vehicles is currently the subject of increased efforts. In view of the complexity of the task and the associated safety aspects, however, it is expected to take decades to fully achieve this objective.
Until then, driver assistance systems represent an intermediate objective, which can take over temporary control over the vehicle in defined, relatively straightforward driving situations, e.g. when traveling on freeways, whereby automatic control of the longitudinal and transversal movements of the vehicle can take place by means of a lane keeping assistant in conjunction with an automatic separation maintenance means in relation to a vehicle ahead.
With said assistance systems, however, it is common that situations can occur that make taking over manual control by the driver necessary. For example, when traveling on a freeway the vehicle ahead can leave the freeway or another vehicle can suddenly cut in. Therefore it must always be possible for the driver to take over control again at very short notice when necessary.
For this purpose it must not only be guaranteed that the driver is awake, but that he can pay the driver assistance systems a certain amount of attention, so that the driver can react quickly enough in case of a transfer of control being necessary.
So-called “dead man circuits” are known from railway traffic and various other applications; with these a driver has to operate a button or a lever (and release it again) at defined time intervals as demanded by a signal; otherwise forced braking is initiated. In this way possible accident damage caused by inattention of the driver of the vehicle should be prevented by the system changing to a safer state in the case of doubt (fail-safe principle).
However, with such a dead man system it is tempting over time to carry out the corresponding operation more or less by reflex, so that these operations can even be carried out “almost when half asleep”. Moreover, it is not always guaranteed by this that the driver will give sufficient attention to the displays of the driver assistance systems.
Finally, the operation of a classic dead man circuit may be perceived by the driver of an automobile as monotonous and hence ultimately as annoying.